Camera body with which various flash devices can be interchangeably used

ABSTRACT

The camera body includes an imaging element, a hot shoe, an internal light source, and a camera controller. The imaging element is configured to convert an optical image of the subject into an electrical signal, and is configured to produce image data for the subject. The hot shoe allows the flash device to be mounted. The internal light source is arranged to shine light on the subject. The camera controller is configured to calculate an evaluation value on the basis of the image data produced by the imaging element, and is configured to perform video autofocusing on the basis of the evaluation value. The camera controller controls the imaging element and the internal light source so that when the camera controller decides that the auxiliary light is needed, and the camera controller decides that the flash device mounted to the hot shoe has an external auxiliary light source arranged to emit near infrared light, the internal light source emits light during the video autofocusing and the image data is acquired.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2008-240478 filed on Sep. 19, 2008. The entire disclosure of JapanesePatent Application No. 2008-240478 is hereby incorporated herein byreference.

TECHNICAL FIELD

The technology disclosed herein relates to a camera body to which anexternal flash device can be mounted.

DESCRIPTION OF THE RELATED ART

Japanese Laid-Open Patent Application 2007-127836 discloses a singlelens reflex camera. This camera has a lens unit and a camera body. Thecamera body is equipped with a CCD (Charge Coupled Device) image sensor,and a mirror box device disposed between the lens unit and the CCD imagesensor. The mirror box device guides the subject light flux from thelens unit to either the CCD image sensor or a prism. The subject lightflux guided to the prism is guided by the prism to a viewfinder.

SUMMARY

However, it is difficult to reduce the size of the camera body with aninterchangeable lens digital camera of this type because the camera bodyis equipped with a mirror box device.

In view of this, the inventors of the present invention came up with anovel interchangeable lens digital camera that has no mirror box device.Also, in the course of further development of a novel interchangeablelens digital camera, the inventors discovered that there are cases whenit is impossible to use the auxiliary light of the flash device that isused along with a conventional single lens reflex camera as long as anautofocus based on image data produced by an imaging element(hereinafter also referred to as video AF (video autofocus)) isemployed.

It is an object of the technology disclosed herein to provide a camerabody with which interchangeability with a variety of flash devices canbe ensured.

The camera body disclosed herein allows the mounting of a lens unit forforming an optical image of a subject and a flash device for shininglight on the subject. This camera body includes an imaging element, ahot shoe, an internal light source, and a camera controller. The imagingelement is configured to convert an optical image of the subject into anelectrical signal, and is configured to produce image data for thesubject. The hot shoe allows a flash device to be mounted. The internallight source is arranged to shine light on the subject. The cameracontroller is configured to calculate an evaluation value on the basisof the image data produced by the imaging element, and is configured toperform video autofocusing on the basis of the evaluation value. Thecamera controller controls the imaging element and the internal lightsource so that when the camera controller decides that an auxiliarylight is needed, and the camera controller decides that the flash devicemounted to the hot shoe has an external auxiliary light source arrangedto emit near infrared light, the internal light source emits lightduring video autofocusing and the image data is acquired.

With this camera body, when the camera controller decides that theauxiliary light is needed, and the camera controller decides that theflash device mounted to the hot shoe has an external auxiliary lightsource arranged to emit near infrared light, the imaging element and theinternal light source are controlled by the camera controller so thatthe internal light source emits light during video autofocusing and theimage data is acquired. Accordingly, even when a flash device having anexternal auxiliary light source arranged to emit light, that is, a flashdevice that is not compatible with video autofocusing, is mounted to thehot shoe, video autofocusing can still be performed using the internallight source, and there is no drop in video autofocusing accuracy evenwith a flash device that is not compatible with video autofocusing. Inother words, interchangeability with various flash devices can beensured with this camera body.

The auxiliary light referred to here includes not only light emitted bya flash device, but also light emitted by the internal light sourcebuilt into the camera body. Whether or not to use auxiliary light can bedecided, for example, by a forced emission mode, an emission prohibitedmode, an automatic emission mode, or another such light emission mode.

The term video autofocusing here means autofocusing on the basis ofimage data produced by an imaging element. Further, the externalauxiliary light source of the flash device is a light source used in anauxiliary capacity, and has a smaller output than the external mainlight source of the flash device

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings, which form a part of thisoriginal disclosure:

FIG. 1 is an oblique view of a digital camera 1;

FIG. 2 is an oblique view of a camera body 100;

FIG. 3 is a block diagram of the digital camera 1;

FIG. 4 is a simplified cross section of the digital camera 1;

FIG. 5 is a rear view of the camera body 100;

FIG. 6 is a block diagram of the digital camera 1 to which an externalflash 300 is mounted;

FIG. 7 is a block diagram of the digital camera 1 to which an externalflash 400 is mounted;

FIG. 8 is a graph of the emission spectrum distribution of auxiliarylight and the spectral transmissivity of an optical filter 114;

FIG. 9 is a flowchart related to the use of auxiliary light during videoautofocusing (first embodiment);

FIG. 10A is a concept diagram of focal position correction whenauxiliary light is used (in the case of internal auxiliary light, or inthe case of external auxiliary light that is compatible with videoautofocusing);

FIG. 10B is a concept diagram of focal position correction whenauxiliary light is used (in the case of external auxiliary light that isincompatible with video autofocusing);

FIG. 11 is a timing chart of the intermittent emission of an externalmain light source 301 during video autofocusing;

FIG. 12 is a flowchart related to the use of auxiliary light duringvideo autofocusing (second embodiment);

FIG. 13 is a flowchart related to the use of auxiliary light duringvideo autofocusing (third embodiment);

FIG. 14 is a flowchart related to the use of auxiliary light duringvideo autofocusing (fourth embodiment); and

FIG. 15 is a flowchart related to the use of auxiliary light duringvideo autofocusing (fifth embodiment).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the art from thisdisclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting theinvention as defined by the appended claims and their equivalents.

First Embodiment 1: Configuration

1-1: Overview of Digital Camera

As shown in FIGS. 1 to 3, a digital camera 1 according to the firstembodiment comprises a camera body 100 and a lens unit 200 that can bemounted to the camera body 100.

Unlike with a single lens reflex camera, the camera body 100 has nomirror box device, so its flange-back is smaller than that of a singlelens reflex camera. Reducing the flange-back also allows the camera body100 to be made more compact. Furthermore, reducing the flange-backaffords greater latitude in design of the optical system, so the lensunit 200 can be made more compact.

For the sake of convenience in the following description, the subjectside of the digital camera 1 will be referred to as the front, theopposite side of the digital camera 1 from the subject as the rear orback, the vertical upper side when the digital camera 1 is in its normalorientation (hereinafter also referred to as landscape orientation) asthe top, and the vertical lower side as the bottom.

1-2: Configuration of Camera Body

As shown in FIGS. 4 and 5, the camera body 100 mainly comprises a CMOS(complementary metal oxide semiconductor) image sensor 110, a CMOScircuit board 113, a camera monitor 120, a control unit 130, a maincircuit board 142 that includes a camera controller 140, a body mount150, a power supply 160, a card slot 170, an electronic viewfinder 180,a shutter unit 190, an optical filter 114, a diaphragm 115, an internalmain light source 191 (an example of an internal light source), aninternal auxiliary light source 192 (an example of an internal lightsource), a hot shoe 161, and a housing member 101.

The body mount 150, the shutter unit 190, the diaphragm 115, the opticalfilter 114, the CMOS image sensor 110, the CMOS circuit board 113, themain circuit board 142, and the camera monitor 120 are disposed in thatorder, starting from the front of the camera body 100.

The CMOS image sensor 110 converts an optical image of the subject(hereinafter also referred to as a subject image) formed by the lensunit 200 into an electrical signal, and produces image data about thesubject. More specifically, the CMOS image sensor 110 has anopto-electrical conversion layer capable of storing electrical chargesby opto-electrical conversion, and a color filter layer provided to thefront face of the opto-electrical conversion layer. The opto-electricalconversion layer has a plurality of pixels, and each pixel is capable ofstoring an electrical charge by opto-electrical conversion. The colorfilter layer has a plurality of blue color filters that only transmitblue light, a plurality of green color filters that only transmit greenlight, and a plurality of red color filters that only transmit redlight. The blue, green, and red color filters are disposed in aone-on-one correspondence with the pixels on the front face of eachpixel of the opto-electrical conversion layer. The CMOS image sensor 110is able to amplify signals from pixels where blue color filters aredisposed, signals from pixels where green color filters are disposed,and signals from pixels where red color filters are disposed. The CMOSimage sensor 110 produces image data on the basis of these signals.

The image data that is produced is digitized by an A/D converter 111(discussed below) of the CMOS circuit board 113. The image datadigitized by the A/D converter 111 is subjected to various imageprocessing by the camera controller 140. The various image processingreferred to here includes, for example, gamma correction processing,white balance correction processing, scratch correction processing,white balance correction processing, scratch correction processing, YCconversion processing, electronic zoom processing, and JPEG compressionprocessing.

The CMOS image sensor 110 operates on the basis of a timing signalcontrolled by a timing generator 112. The CMOS image sensor 110 canperform acquisition of still picture data and moving picture data undercontrol by the CMOS circuit board 113. The moving picture data thusacquired is also used for the display of through-images.

A “through-image” here is an image out of the image data that is notrecorded to a memory card 171. Through-images are primarily movingpictures, and are displayed on the camera monitor 120 and the electronicviewfinder 180 (hereinafter also referred to as EVF) to decide thecomposition of a moving or still picture.

The CMOS image sensor 110 is an example of an imaging element thatconverts an optical image of a subject into an electrical image. Theimaging element is a concept that encompasses the CMOS image sensor 110as well as a CCD image sensor or other such opto-electrical conversionelement.

The CMOS circuit board 113 is a circuit board that controls the drive ofthe CMOS image sensor 110. The CMOS circuit board 113 is also a circuitboard that subjects the image data outputted from the CMOS image sensor110 to specific processing, and as shown in FIG. 3, includes the timinggenerator 112 and the A/D converter 111. The CMOS circuit board 113 isan example of an imaging element circuit board that controls the driveof the imaging element and subjects the image data outputted from theimaging element to A/D conversion and other such specific processing.

The camera monitor 120 is a liquid crystal display, for example, anddisplays display-use image data as an image. The display-use image datais image data that has undergone image processing, or data fordisplaying the photography conditions of the digital camera 1, a controlmenu, or the like as an image, and is produced by the camera controller140, for example. The camera monitor 120 is capable of selectivelydisplaying both moving and still pictures.

As shown in FIG. 5, the camera monitor 120 is disposed on the rear faceof the camera body 100. The camera monitor 120 may be disposed anywhereon the camera body 100. The camera monitor 120 is such that the angle ofthe display screen can be varied with respect to the housing member 101.More specifically, as shown in FIGS. 1, 2, and 5, the camera body 100has a hinge 121 that rotatably links the housing member 101 and thecamera monitor 120. The hinge 121 is disposed at the left end of thecamera body 100 as viewed from the rear face side in landscapeorientation. The hinge 121 has a first rotation axis disposed parallelto the vertical direction in landscape orientation, and a secondrotation axis disposed parallel to the horizontal plane in landscapeorientation. The orientation of the camera monitor 120 with respect tothe housing member 101 can be changed as desired by rotating the cameramonitor 120 around the first and second rotation axes.

The camera monitor 120 is an example of a display unit provided to thecamera body 100. Other examples include an organic electroluminescenceunit, and inorganic electroluminescence unit, a plasma display panel,and other such devices that allow images to be displayed. The displayunit need not be disposed on the rear face of the camera body 100, andmay instead be provided to a side face, the top face, or another suchplace.

The electronic viewfinder 180 displays the display-use image dataproduced by the camera controller 140 as an image. The EVF 180 iscapable of selectively displaying both moving and still pictures. TheEVF 180 and the camera monitor 120 may display the same or differentcontent, and both are controlled by the camera controller 140. The EVF180 has an EVF-use liquid crystal monitor 181 that displays images andthe like, an EVF-use optical system 182 that enlarges the display of theEVF-use liquid crystal monitor, and an eyepiece 183 up to which the userputs an eye.

The EVF 180 is also an example of a display unit. The EVF 180 differsfrom the camera monitor 120 in that the user puts an eye up to it. Thedifference in terms of structure is that whereas the EVF 180 has theeyepiece 183, the camera monitor 120 does not have an eyepiece 183.

The proper display brightness of the EVF-use liquid crystal monitor 181is ensured by providing a back light (not shown) in the case of atransmission type of liquid crystal, and a front light in the case of areflection type of liquid crystal. The EVF-use liquid crystal monitor181 is an example of an EVF-use monitor. The EVF-use monitor can be anorganic electroluminescence unit, and inorganic electroluminescenceunit, a plasma display panel, or another such device that allows imagesto be displayed. There is no need for an illumination light source inthe case of an organic electroluminescence unit or other suchself-emitting device.

The control unit 130 receives commands from the user. More specifically,as shown in FIGS. 1 and 2, the control unit 130 has a release button 131that is used for shutter operation by the user, and a power switch 132that is a rotary dial switch provided to the top face of the camera body100. The release button 131 is used for shutter operations by the user.The power switch 132 is such that the power is off in a first rotationposition, and the power is on in a second rotation position. The controlunit 130 encompasses a button, lever, dial, touch panel, or the like, solong as it can be operated by the user.

The camera controller 140 is disposed on the main circuit board 142, andcontrols the entire camera body 100, including the CMOS image sensor 110and other such components. The camera controller 140 is electricallyconnected to the control unit 130, and control signals are inputted fromthe control unit 130. The camera controller 140 uses a DRAM 141 as aworking memory during control operations and image processingoperations.

The camera controller 140 sends a signal for controlling the lens unit200 to a lens controller 240 via the body mount 150 and a lens mount250, and indirectly controls the components of the lens unit 200. Thecamera controller 140 also receives various kinds of signals from thelens controller 240 via the body mount 150 and the lens mount 250.Specifically, the camera controller 140 controls the entire digitalcamera 1. The camera controller 140 is an example of a body controller.

The camera controller 140 has a CPU (central processing unit), a ROM(read only memory, and a RAM (random access memory), and variousfunctions can be carried out by reading programs stored in the ROM intothe CPU. The functions of the camera controller 140 will be discussedbelow.

The card slot 170 allows the memory card 171 to be inserted. The cardslot 170 controls the memory card 171 on the basis of control from thecamera controller 140. More specifically, the card slot 170 stores imagedata on the memory card 171 and outputs image data from the memory card171. For example, the card slot 170 stores image data on the memory card171 and outputs moving picture data from the memory card 171.

The memory card 171 is able to store the image data produced by thecamera controller 140 in image processing. For instance, the memory card171 can store uncompressed raw image files, compressed JPEG image files,or the like. Also, image data or image files that have been internallystored ahead of time can be outputted from the memory card 171 via thecard slot 170. The image data or image files outputted from the memorycard 171 are subjected to image processing by the camera controller 140.For example, the camera controller 140 produces display-use image databy subjecting the image data acquired from the memory card 171 toexpansion, etc.

The memory card 171 is further able to store video data produced by thecamera controller 140 in image processing. For instance, the memory card171 can store video files compressed according to H.264/AVC, which is avideo compression standard. The memory card 171 can also output, via thecard slot 170, video data or video files internally stored ahead oftime. The video data or video files outputted from the memory card 171are subjected to image processing by the camera controller 140. Forexample, the camera controller 140 subjects the video data or videofiles acquired from the memory card 171 to expansion processing andproduces display-use video data.

The memory card 171 is also an example of a recording unit that recordselectrical signals produced by the imaging element. The recording unitmay be one that can be mounted to the camera body 100, such as thememory card 171, or may be one that is built into the digital camera 1.

The power supply 160 supplies electrical power to the various componentsof the digital camera 1. The power supply 160 may, for example, be a drycell, or may be a rechargeable cell. The power supply 160 also may be anexternal power supply that supplies power to the digital camera 1 via apower cord or the like.

The body mount 150 allows the lens unit 200 to be mounted, and supportsthe lens unit 200 in a state in which the lens unit 200 is mounted. Thebody mount 150 can be mechanically and electrically connected with thelens mount 250 of the lens unit 200. Data and/or control signals can besent and received between the camera body 100 and the lens unit 200 viathe body mount 150 and the lens mount 250. More specifically, dataand/or control signals can be sent and received between the body mount150 and the lens mount 250, and between the camera controller 140 andthe lens controller 240. The body mount 150 supplies power received fromthe power supply 160 to the entire lens unit 200 via the lens mount 250.

More specifically, the body mount 150 includes a body mount ring 151 anda body mount contact support part 152. The body mount ring 151 is eitherin a state of being mated with a lens mount ring 251 or a state of notbeing mounted, depending on the rotational position relation to the lensmount ring 251 of the lens unit 200 around the optical axis AX.Specifically, when the rotational position relation of the body mountring 151 and the lens mount ring 251 is in a first state, the lens mountring 251 is not mated with the body mount ring 151, and the lens mountring 251 is able to move in a direction parallel to the optical AX withrespect to the body mount ring 151 (hereinafter referred to as theoptical axis direction). That is, the lens mount ring 251 can be removedfrom the body mount ring 151.

When the lens mount ring 251 is inserted into the body mount ring 151 inthe first state, and the lens mount ring 251 is rotated with respect tothe body mount ring 151, the lens mount ring 251 mates with the bodymount ring 151. If we call the rotational position relation between thebody mount ring 151 and the lens mount ring 251 here a second state,then when the rotational position relation is in the second state, thebody mount ring 151 mechanically supports the lens unit 200. Since thebody mount ring 151 mechanically supports the lens unit 200, the bodymount ring 151 needs to have a certain amount of strength. Therefore,the body mount ring 151 is preferably formed from metal.

The body mount contact support part 152 is disposed between the bodymount ring 151 and the shutter unit 190, and has a plurality ofelectrical contacts 153. In a state in which the lens unit 200 ismounted to the body mount 150, the plurality of electrical contacts 153are in respective contact with a plurality of electrical contacts 253had by the lens mount 250. In a state in which the electrical contacts153 of the body mount 150 are in contact with the electrical contacts253 of the lens mount 250, the body mount 150 and the lens mount 250 canbe electrically connected. Also, the supply of power and the exchange ofdata and control signals are performed between the camera body 100 andthe lens unit 200 via the electrical contacts 153 of the body mount 150and the electrical contacts 253 of the lens mount 250.

As shown in FIG. 2, the body mount contact support part 152 has anopening, and is disposed between the body mount ring 151 and the shutterunit 190.

The shutter unit 190 is what is known as a focal plane shutter, and isdisposed between the body mount 150 and the CMOS image sensor 110. Theshutter unit 190 can maintain an open state mechanically. The shutterunit 190 is controlled by the camera controller 140 so that an openstate is maintained when power is shut off to the camera body 100. Theconcept of mechanically maintaining an open state here means that theopen state is maintained without the use of electrical power. Specificexamples of ways to maintain an open state mechanically include aconfiguration in which a specific member is used to support a frontcurtain and a rear curtain at a position corresponding to the openstate, and a configuration in which the front curtain and the rearcurtain are supported at a position corresponding to the open state bythe force of a permanent magnet.

The optical filter 114 has the function of an optical low-pass filterthat eliminates the high-frequency component of the subject light. Morespecifically, the optical filter 114 separates a subject image formed bythe lens unit 200 so that the resolution is coarser than the pitch ofthe pixels of the CMOS image sensor 110. In general, an imaging elementsuch as the CMOS image sensor has an RGB color filter called a Bayerpattern, or a YCM complementary color filter, provided for each pixel.Therefore, if the resolution goes to one pixel, not only will a falsecolor be generated, but if the subject is a repeating pattern, anunattractive moire will result. Furthermore, the optical filter 114 hasan Ir cut filter function for cutting out infrared light with awavelength of approximately 700 nm or higher.

The diaphragm 115 is disposed in front (the subject side) of the CMOSimage sensor 110, and prevents dust from clinging to the CMOS imagesensor 110. Also, any dust clinging to the diaphragm 115 itself isknocked off by the vibration of the diaphragm 115. More specifically,the diaphragm 115 has a thin, transparent sheet-like member and apiezoelectric element that imparts vibration to the sheet-like member.The piezoelectric element is fixed to a frame (not shown). AC voltage isapplied to the piezoelectric element, which causes the piezoelectricelement to vibrate, and this vibrates the sheet-like member and knocksoff any dust clinging to the sheet-like member.

The internal main light source 191 is a light source that shines flashlight on the subject and, during moving picture capture, illuminates thesubject by shining a flash at the subject. The internal main lightsource 191 is controlled by the camera controller 140. In thisembodiment, the flash of the internal main light source 191 is whitelight.

The internal auxiliary light source 192 is a light source for shininglight on the subject during autofocusing, and emits visible light thatincludes the color red. In this embodiment, the internal auxiliary lightsource 192 emits light in which the wavelength of the peak intensity ofthe spectral characteristics is 612 nm. The internal auxiliary lightsource 192 is an LED, for example.

The hot shoe 161 is disposed at the upper part of the camera body 100.An external flash or other such flash device can be mounted to the hotshoe 161. When a flash device is mounted to the hot shoe 161, the flashdevice is supported by the hot shoe 161. The hot shoe 161 has a datasignal terminal 162, an XSW signal terminal 163, and an external flashdetection terminal 164, and comes into contact with the terminals of theexternal flash 300. Consequently, the camera body 100 and the externalflash 300 can be synchronized, and the external flash 300 can emit lightin conjunction with the operating timing of the shutter (or the chargeaccumulation timing of the CMOS image sensor 110). If the internal mainlight source 191 and the internal auxiliary light source 192 are madesmaller, they emit less light, and not enough light may reach a distantsubject, but greater photographic freedom is ensured for the user bybeing able to mount the external flash 300, which emits more light.

1-3: Configuration of Lens Unit

The lens unit 200 comprises an optical system, the lens controller 240,the lens mount 250, an aperture unit 260, and a lens barrel 290. Theoptical system of the lens unit 200 includes a zoom lens 210, an OISlens 220, and a focus lens 230. The optical system is housed in theinterior of the lens barrel 290. A zoom ring 213, a focus ring 234 andan OIS switch 224 are provided on the outside of the lens barrel.

The zoom lens 210 is used to change the magnification of an opticalimage of a subject (hereinafter also referred to as a subject image)formed by the optical system of the lens unit 200, or in other words, tochange the focal distance of the optical system. The zoom lens 210 ismade up of one or more lenses. The zoom lens 210 includes a first lensgroup L1 and second lens group L2 of the optical system. The focaldistance of the optical system changes when the zoom lens 210 moves in adirection parallel to the optical axis AX.

The zoom ring 213 is a cylindrical member that is able to rotate on theouter peripheral face of the lens barrel 290. The zoom ring 213 is anexample of a zoom control that adjusts the focal distance, and is anexample of a zoom control that decides the focal distance according tothe position after operation.

When the user operates the zoom ring 213, a drive mechanism 211transmits this operation to the zoom lens 210, and moves the zoom lens210 along the optical axis AX direction of the optical system.

A detector 212 detects the amount of drive of the drive mechanism 211.The lens controller 240 and/or the camera controller 140 acquires adetection result from this detector 212, and ascertains the focaldistance in the optical system. Also, the lens controller 240 and/or thecamera controller 140 acquires a detection result from this detector212, and ascertains the position of the zoom lenses (L1, L2, etc.) at aposition in the optical axis AX direction within the lens unit 200. Thedrive mechanism 211 should be able to move the zoom lens 210 in theoptical axis AX direction. For example, the drive mechanism 211 maytransfer the drive force from a motor or other such drive forcegenerator to the zoom lens 210 according to the rotational position ofthe zoom ring 213 or another such control, and move the zoom lens 210 toa position in the optical axis AX direction that corresponds to therotational position of the zoom ring 213.

The OIS lens 220 is used to correct blurring of a subject image formedby the optical system of the lens unit 200. The OIS lens 220 correctsblurring of the subject image caused by shake of the digital camera 1.When the OIS lens 220 is moved in the direction in which the OIS lens220 cancels out shake of the digital camera 1, relative shake betweenthe CMOS image sensor 110 and the subject image is reduced. The OIS lens220 is made up of one or more lenses. An actuator 221 is controlled byan OIS-use IC 223 and drives the OIS lens 220 within a planperpendicular to the optical axis AX of the optical system.

The actuator 221 can comprise, for example, a magnet and a planar coil.A position detection sensor 222 detects the position of the OIS lens 220within a plane perpendicular to the optical axis AX. The positiondetection sensor 222 can comprise, for example, a magnet and a Hallelement. The OIS-use IC 223 controls the actuator 221 on the basis of adetection result of a gyro sensor or other such shake detector and adetection result of the position detection sensor 222. The OIS-use IC223 obtains a detection result of the shake detector from the lenscontroller 240. The OIS-use IC 223 also sends the lens controller 240 asignal indicating the status of optical image blur correctionprocessing.

The OIS lens 220 is an example of a blur corrector. Electronic blurcorrection that produces image data corrected on the basis of image datafrom the CMOS image sensor 110 may be employed as a means for correctingblurring of the subject image caused by shake of the digital camera 1.Also, a configuration in which the CMOS image sensor 110 is drivenwithin a plane perpendicular to the optical axis AX of the opticalsystem may be used as a means for reducing relative shake between theCMOS image sensor 110 and the subject image caused by shake of thedigital camera 1.

The OIS switch 224 is an example of a control for operating the OIS.When the OIS switch 224 is switched off, the OIS lens 220 does notoperate. When the OIS switch 224 is switched on, the OIS lens 220 isable to operate.

The focus lens 230 is used to change the focal state of the subjectimage formed on the CMOS image sensor 110 by the optical system. Thefocus lens 230 is made up of one or more lenses. The zoom lens 210changes the focal state of the subject image by moving in a directionparallel to the optical axis AX of the optical system.

A focus motor 233 drives the focus lens 230 so that it moves back andforth along the optical axis AX, under control by the lens controller240. Consequently, the focal state of the subject image formed on theCMOS image sensor 110 by the optical system can be changed. The focusmotor 233 can drive the focus lens 230 independently from the drive ofthe zoom lens 210. More specifically, the focus motor 233 drives thefocus lens 230 in the optical axis AX direction using the second lensgroup L2 as a reference. In other words, the focus motor 233 is able tochange the relative distance between the second lens group L2 and thefocus lens 230 in the optical axis AX direction. The focus lens 230 andthe focus motor 233 move in the optical axis AX direction along with thesecond lens group L2. Therefore, when the second lens group L2 moves inthe optical axis AX direction because of zoom operation, the focus lens230 and the focus motor 233 also move in the optical axis AX direction.Also, the focus motor 233 can drive the focus lens 230 in the opticalaxis AX direction using the second lens group L2 as a reference even ina state in which the second lens group L2 is stopped in the optical axisAX direction. The focus motor 233 can be a DC motor, a stepping motor, aservo motor, an ultrasonic motor, or the like.

A relative position detector 231 and an absolute position detector 232are encoders that produce signals indicating the drive state of thefocus lens 230. The relative position detector 231 has a magnetic scaleand a magnetic sensor, and detects magnetic changes and outputs signalscorresponding to magnetic changes. An example of a magnetic sensor is anMR sensor. The absolute position detector 232 is a home detector thatdetects the home position of the focus lens 230 with respect to thesecond lens group L2. The absolute position detector 232 is aphotosensor, for example. The lens controller 240 recognizes that thefocus lens 230 is at its home point from a signal from the absoluteposition detector 232. At this point the lens controller 240 resets thevalue of a counter 243 that is provided internally. This counter 243counts the extreme values of magnetic changes by using signals outputtedfrom the relative position detector 231. Consequently, the lenscontroller 240 is able to ascertain the position of the focus lens 230in the optical axis AX direction with respect to the second lens groupL2 by detecting the relative position from the home position, which isan absolute position. Also, as mentioned above, the lens controller 240is able to ascertain the position of the second lens group L2 in theoptical axis AX direction within the lens unit 200. Therefore, the lenscontroller 240 is able to ascertain the position of the focus lens 230in the optical axis AX direction within the lens unit 200.

The aperture unit 260 is a light quantity adjusting member that adjustthe quantity of light transmitted by the optical system. The apertureunit 260 has aperture vanes that can block part of the light raystransmitted by the optical system, and an aperture driver that adjuststhe quantity of light by driving the aperture vanes and varying theamount of blockage thereof. The camera controller 140 controls theoperation of the aperture unit 260 on the basis of the quantity of lightreceived by the CMOS image sensor 110, whether still picture or movingpicture photography is to be performed, whether or not there is anoperation to which an aperture value is preferentially set, and soforth.

The lens controller 240 controls the various components of the lens unit200, such as the OIS-use IC 223 and the focus motor 233, on the basis ofcontrol signals from the camera controller 140. The lens controller 240also receives signals from the detector 212, the OIS-use IC 223, therelative position detector 231, the absolute position detector 232, andso forth, and sends these to the camera controller 140. The lenscontroller 240 communicates with the camera controller 140 via the lensmount 250 and the body mount 150. The lens controller 240 uses a DRAM241 as a working memory during controlling. Also, a flash memory 242stores programs and parameters used in control by the lens controller240.

1-4: External Flash

FIG. 6 is a block diagram of the digital camera 1 when an external flash300 (an example of a flash device) is mounted. The external flash 300comprises the external main light source 301, an external auxiliarylight source 302, a flash controller 303, a hot shoe mount 304, and apower supply 305.

The hot shoe mount 304 is mounted to the hot shoe 161 of the camera body100. The hot shoe mount 304 has a data signal terminal 362, an XSWsignal terminal 363, and an external flash detection terminal 364. Theterminals 362, 363, and 364 are in contact with the data signal terminal162, the XSW signal terminal 163, and the external flash detectionterminal 164 of the camera body 100, respectively. The data signalterminal 362 and the XSW signal terminal 363 are connected to the flashcontroller 303. The external flash detection terminal 364 is connectedto an electrical ground.

The flash controller 303 controls the various components of the externalflash 300, such as the external main light source 301 and the externalauxiliary light source 302. The external main light source 301 emits awhite flash under the control of the flash controller 303. The externalauxiliary light source 302 emits visible light including red light underthe control of the flash controller 303. In this embodiment, the lightis emitted in which the wavelength of the peak intensity of the spectralcharacteristics is 612 nm. The power supply 305 supplies power to thevarious components of the external flash 300.

When the external flash 300 is mounted to the camera body 100, theexternal flash detection terminal 164 and the external flash detectionterminal 364 are electrically connected. An external flash detector 144of the camera controller 140 detects if the voltage of the externalflash detection terminal 164 is at ground level, and thereby decideswhether or not the external flash 300 is mounted to the hot shoe 161.

FIG. 7 is a block diagram of the digital camera 1 when an external flash400 (an example of a flash device) of a comparative example is mounted.With this external flash 400, the light emitted by an external auxiliarylight source 402 is usually near infrared light. This is because lightwith a long wavelength such as near infrared light is less susceptibleto attenuation and tends to travel farther, and because light with along wavelength such as near infrared light is more readily detected bythe phase difference detection units commonly used with single lensreflex cameras. Another reason for using near infrared light is thathumans do not perceive it to be bright. The term “near infrared light”refers to light whose wavelength is at least about 700 nm, for example,and more specifically refers to light in which the wavelength of thepeak energy intensity of the spectral characteristics is at least about700 nm. The term “spectral characteristics” refers to the energyintensity distribution seen for each wavelength had by the emittedlight. These spectral characteristics are also called the emissionspectrum.

The external auxiliary light source 302 of the external flash 300 ischaracterized in that it emits light of a shorter wavelength than thelight emitted by the external auxiliary light source 402 of the externalflash 400 in a comparative example.

1-5: Camera Controller

As discussed above, the camera controller 140 has various functions. Forexample, as shown in FIG. 3, it has the external flash detector 144, anexternal flash decision part 145 (an example of a flash device decisionpart), an auxiliary light decision part 146 (and example of an auxiliarylight decision part), and a light emission controller 147.

The external flash detector 144 decides whether or not an external flashis mounted to the hot shoe 161. More specifically, the external flashdetector 144 decides whether or not the external flash 300 is mounted tothe hot shoe 161 by detecting the voltage of the external flashdetection terminal 164. If the voltage of the external flash detectionterminal 164 is at ground level, the external flash detector 144 decidesthat an external flash is mounted to the hot shoe 161, and if thevoltage of the external flash detection terminal 164 is higher thanground level, it is decided that an external flash has not been mountedto the hot shoe 161.

The external flash decision part 145 decides whether or not the externalflash mounted to the hot shoe 161 is compatible with video autofocusing.More specifically, a flash controller is installed in the externalflash, and video autofocusing information indicating whether or not anexternal flash is compatible with video autofocusing (an example ofspecification identification information) is stored at a specificaddress of the flash controller. The external flash decision part 145acquires video autofocusing information from the flash controller, anddecides whether or not the external flash is compatible with videoautofocusing on the basis of the acquired video autofocusinginformation.

More precisely, if an external flash is compatible with videoautofocusing, the video autofocusing information includes dataindicating “video autofocusing compatible,” and if the external flash isnot compatible with video autofocusing, the video autofocusinginformation includes data indicating “video autofocusing incompatible.”If the external flash has an external main light source and an externalauxiliary light source, and the video autofocusing information is videoautofocusing compatible, that means that the external auxiliary lightsource is compatible with video autofocusing, and if the videoautofocusing information is video autofocusing incompatible, that meansthat the external auxiliary light source is not compatible with videoautofocusing. In this embodiment, since the camera body 100 has theoptical filter 114, when the external auxiliary light source emits redlight, the external auxiliary light source is compatible with videoautofocusing, and when the external auxiliary light source emitsinfrared light or near infrared light, the external auxiliary lightsource is compatible with video autofocusing.

If video autofocusing information itself is not stored at a specificaddress of the flash controller, the external flash decision part 145cannot acquire video autofocusing information from the flash controller.In this case, it is possible that the external flash is not compatiblewith video autofocusing, and the external flash decision part 145decides that the external flash is not compatible with videoautofocusing.

The auxiliary light decision part 146 decides whether or not to useauxiliary light on the basis of the selected emission mode. The emissionmode is selected by using a menu displayed on the camera monitor 120,for example. Possible emission modes include a mode in which auxiliarylight is forcibly used (forced emission mode), a mode in which the useof auxiliary light is prohibited (emission prohibited mode), and a modein which the use of auxiliary light is automatically selected (automaticemission mode). The auxiliary light decision part 146 decides to useauxiliary light if the forced emission mode is selected, and decides notto use auxiliary light if the emission prohibited mode is selected.Furthermore, if the automatic emission mode is selected, it is decidedto use auxiliary light if the brightness of an image reproduced by imagedata outputted from the CMOS image sensor 110 is lower than a specificreference brightness. The system may also be such that it is decided notto use auxiliary light if the camera is too far from the subject.

The light emission controller 147 controls the internal main lightsource 191, the internal auxiliary light source 192, or an externalflash mounted to the hot shoe 161, according to the emission mode thatis set. More specifically, if the emission mode is set to forcedemission mode, the light emission controller 147 causes the internalmain light source 191, the internal auxiliary light source 192, or theexternal flash to emit light during photography. If the emission mode isset to automatic emission mode and the brightness of the image is low,it causes the internal main light source 191, the internal auxiliarylight source 192, or the external flash to emit light duringphotography.

If it is decided by the external flash detector 144 that an externalflash is mounted to the hot shoe 161, the light emission controller 147uses the external flash preferentially on the basis of this decisionresult.

The light emission controller 147 controls the external flash so thatthe external main light source of the external flash emits lightintermittently during video autofocusing on the basis of the decisionresult of the auxiliary light decision part 146 and the external flashdecision part 145. More specifically, when the auxiliary light decisionpart 146 decides that auxiliary light is to be used, and the externalflash decision part 145 decides that the external flash is notcompatible with video autofocusing, the light emission controller 147controls the external flash so that the external main light source emitslight intermittently. This control of intermittent light emission willbe discussed below.

The auxiliary light decision part 146 is an example of a first decisionresult, and the decision result of the external flash detector 144 is anexample of a second decision result.

2: Autofocus

2-1: Video Autofocusing

The camera body 100, unlike a single lens reflex camera, does not have amirror box device, nor does it have a phase difference detection unitthat receives light guided by a mirror box device and performs phasedifference autofocusing. The camera body 100 performs autofocusing onthe basis of image data obtained by the CMOS image sensor 110. Morespecifically, the position of the focus lens 230 is changed to outputsequential image data from the CMOS image sensor 110, and a contrastevaluation value is calculated on the basis of each piece of image data.The focal state can be adjusted by moving the focus lens 230 to theposition of the focus lens 230 corresponding to the greatest evaluationvalue calculated. Autofocusing such as this is defined as videoautofocusing.

With the above-mentioned video autofocusing, if the subject is dark, thecontrast will be low in an image reproduced from the acquired imagedata, and it will be difficult to obtain an evaluation value with whichvideo autofocusing precision can be ensured.

In view of this, if the subject is dark on the basis of image data, itis possible to shine light on the subject by having the internalauxiliary light source 192 emit light. FIG. 8 is a graph of the spectralcharacteristics of auxiliary light and the spectral transmissivity ofthe optical filter 114. The internal auxiliary light source 192 emitslight that is not cut out by the optical filter 114. More specifically,the optical filter 114 cuts out light whose wavelength is longer thanthat of red light (mainly near infrared light), but the internalauxiliary light source 192 emits red light that is not readily cut outby the optical filter 114. Therefore, any light that is shined by theinternal auxiliary light source 192 on the subject and reflected by thesubject is transmitted through the optical filter 114 and reaches theCMOS image sensor 110.

2-2: When an External Flash is Mounted

The internal main light source 191 and the internal auxiliary lightsource 192 emit less light when made smaller in size. Accordingly, ifthe subject is so distant from the photography site that the light ofthe internal main light source 191 or the internal auxiliary lightsource 192 will not reach the subject, or if the subject cannot beilluminated brightly enough, an externally attached flash device such asthe external flash 300 is used. With an externally attached flashdevice, the camera body 100 does not become any bulkier, a large lightsource with a large quantity of light can be used, and a sufficientquantity of light can be ensured.

The external auxiliary light source 302, which emits light that is notreadily cut out by the optical filter 114, is employed for the externalflash 300 corresponding to the camera body 100. More specifically, theexternal auxiliary light source 302 emits red light that is not readilycut out by the optical filter 114. Accordingly, even if the externalauxiliary light source 302 is used during autofocusing, for example, theevaluation value can still be calculated accurately, and autofocusingprecision can be ensured. Therefore, if an external flash 300corresponding to video autofocusing is mounted to the camera body 100,and it is decided that auxiliary light is necessary to acquire anevaluation value, then the camera controller 140 controls the externalflash 300 so that the external auxiliary light source 302 emits lightduring video autofocusing.

With the external flash 400 in a comparative example, however, the lightemitted by the external auxiliary light source 402 is near infraredlight. Accordingly, when the external auxiliary light source 402 isused, light incident on the lens unit 200 from a subject illuminated bythe external auxiliary light source 402 is cut out by the optical filter114, and not enough light reaches the CMOS image sensor 110. Thus, ifvideo autofocusing is performed using the external flash 400, there isthe risk of diminished autofocusing precision. That is, unlike with theexternal flash 300, the external flash 400 can be considered to be aflash device that is not compatible with video autofocusing.

In view of this, with the camera body 100 in this embodiment, if aexternal flash 400 that is not compatible with video autofocusing ismounted, the external auxiliary light source 402 is not used, and videoautofocusing is performed using the external main light source 301instead. FIG. 9 is a flowchart related to the use of auxiliary lightduring video autofocusing.

When the release button 131 is pressed to start video autofocusing (stepS01), the camera controller 140 decides whether or not to use auxiliarylight (step S02). More specifically, whether or not to use auxiliarylight is decided by the auxiliary light decision part 146. For example,the auxiliary light decision part 146 decides to use auxiliary light ifa mode in which the flash is used forcibly (forced emission mode) isset, and decides not to use auxiliary light if a mode in which the useof a flash is prohibited (emission prohibited mode) is set. If a mode inwhich the use of a flash is automatically selected (automatic emissionmode) is set, then if the brightness of an image reproduced by imagedata outputted from the CMOS image sensor 110 is less than a specificreference brightness, the auxiliary light decision part 146 decides touse auxiliary light. It may also decide not to use auxiliary light ifthe subject is too far away. If the auxiliary light decision part 146has decided not to use auxiliary light (No in step S02), videoautofocusing is performed without the use of auxiliary light (step S03).More specifically, the control of the light source by the light emissioncontroller 147 is not performed in video autofocusing in this situation.

On the other hand, if the auxiliary light decision part 146 decides touse auxiliary light (Yes in step S02), the camera controller 140 decideswhether or not an external flash is mounted to the hot shoe 161 of thecamera body 100 (step SO4). More specifically, it is decided by theexternal flash detector 144 whether or not an external flash is mountedto the hot shoe 161. If the external flash detector 144 decides that noexternal flash is mounted (No in step SO4), the light emissioncontroller 147 causes the internal auxiliary light source 192 to emitlight, and the camera controller 140 performs video autofocusing in astate in which light is shined on the subject (step S05). Here, sincethe evaluation value is calculated in a state in which light from theinternal auxiliary light source 192 is shined on the subject, the focusof the light from the internal auxiliary light source 192 (hereinafteralso referred to as internal auxiliary light) is located on the imagingface of the CMOS image sensor 110 at the position of the focus lens 230with the greatest evaluation value.

However, since no internal auxiliary light is used in actually acquiringimage data, the wavelength of the light when video autofocusing isperformed is different from the wavelength of light during actualphotography. Since the focal position varies with the wavelength oflight, the focal position of the internal auxiliary light is differentfrom the focal position of light during photography.

Therefore, it is necessary to correct so that the focal point of lightduring photography is located on the imaging face of the CMOS imagesensor 110. This will be described in detail through reference to FIGS.10A and 10B. FIG. 10A is a concept diagram of focal position correctionwhen auxiliary light is used. FIG. 10A is a concept diagram of focalposition correction in the case of internal auxiliary light or in thecase of video autofocusing compatible external auxiliary light.

As shown in FIG. 10A, with the lens unit 200, reference light of aspecific wavelength is decided as the light used during photography, andthe amount of deviation in the focal position of the reference light andthe focal position of the internal auxiliary light corresponding to theposition of the focus lens 230 and the position of the zoom lens 210,respectively, is calculated or measured as a design value. The lens unit200 stores an amount X1 (hereinafter also referred to as the firstcorrection amount) that the focus lens 230 is moved in order to correctthe deviation in the focal position of the internal auxiliary light andthe focal position of the reference light, according to the position ofthe zoom lens 210 and the position of the focus lens 230, respectively.Put another way, the first correction amount X1 is informationindicating how much the focus lens 230 has to be moved from a state inwhich the internal auxiliary light is focused on the CMOS image sensor110 for the reference light to be focused on the CMOS image sensor 110.A correction part 148 of the camera controller 140 acquires from thelens controller 240 of the lens unit 200 data related to the relationbetween the first correction amount X1 and the position of the zoom lensand the position of the focus lens 230 when the lens unit 200 is mountedor when the power is turned on, for example. When the internal auxiliarylight is shined on the subject and video autofocusing is performed (stepS05), the focus lens 230 is moved from its position at which theevaluation value was greatest, by the first correction amount X1corresponding to the position of the focus lens 230 and the position ofthe zoom lens. Consequently, the reference light is focused on the CMOSimage sensor 110. The reference light is light that has a wavelengthwith high spectral characteristics, such as sunlight or fluorescentlight. For example, green light may be used as the reference light.

Returning to FIG. 9, if the external flash detector 144 decides that anexternal flash is mounted (Yes in step SO4), the external flash decisionpart 145 decides whether or not the external flash is compatible withvideo autofocusing (step S06). More specifically, video autofocusinginformation is stored ahead of time in the flash controller 303, forexample, and the external flash decision part 145 requests thisinformation from the flash controller 303. The external flash decisionpart 145 decides that the mounted external flash is compatible withvideo autofocusing if the received video autofocusing informationindicates video autofocusing compatibility (Yes in step S06), anddecides that the mounted external flash is not compatible with videoautofocusing if the video autofocusing information indicates videoautofocusing incompatibility or if the external flash decision part 145could not acquire video autofocusing information (No in step S06). Thevideo autofocusing information is set to video autofocusing incompatibleif the light of the external auxiliary light source is near infraredlight, and is set to video autofocusing compatible if the light of theexternal auxiliary light source is visible light that includes redlight. That is, the video autofocusing information can also be calledlight source identification information for deciding whether or not theexternal flash has an external auxiliary light source that emits nearinfrared light. It can be decided that the external flash has anexternal auxiliary light source that emits near infrared light if thevideo autofocusing information is video autofocusing incompatible, andit can be decided that the external flash does not have an externalauxiliary light source that emits near infrared light if the videoautofocusing information is video autofocusing incompatible.

If it is decided that the external flash is compatible with videoautofocusing (Yes in step S06), such as when the external flash 300 ismounted, the camera controller 140 issues a command to the flashcontroller 303 so that the external auxiliary light source 302 emitslight, and the flash controller 303 causes the external auxiliary lightsource 302 to emit light on the basis of this command. Videoautofocusing is performed in a state in which light is shined on thesubject (step S07). Here, just as with video autofocusing internalauxiliary light (step S05), the first correction amount X1 is used tocorrect any deviation that occurs between the focal position of thelight of the external auxiliary light source 302 and the focal positionof the reference light.

If it is decided that the external flash is not compatible with videoautofocusing (No in step S06), such as when the external flash 400 ismounted to the hot shoe 161, then the light emission controller 147causes the external main light source 301 to emit light intermittentlyvia the flash controller 303, and video autofocusing is performed in astate in which light is shined intermittently on the subject (step S08).More specifically, the intermittent emission by the external main lightsource 301 is synchronized with the acquisition of image data forcalculating the evaluation value, and continues during the exposureperiod for acquiring image data.

A specific example of the intermittent emission by the external mainlight source 301 (step S08) will be described in detail throughreference to FIG. 11. FIG. 11 is a timing chart of the intermittentemission of the external main light source 301 during videoautofocusing.

The camera controller 140 generates video synchronization signals at aspecific period, such as 30 Hz or 60 Hz. The timing generator 112controls the operation of the CMOS image sensor 110 in synchronizationwith the video synchronization signals. The CMOS image sensor 110performs charge accumulation by exposure and the reading of the chargein synchronization with the video synchronization signals. Morespecifically, charge accumulation and charge reading is performed fromthe line above the CMOS image sensor 110. The timing at which thecharges are read, that is, the timing at which the accumulation ofcharges is begun, is staggered from the line above.

When an evaluation value is calculated on the basis of image data for apartial region (autofocusing region) of the CMOS image sensor 110, thecamera controller 140 extracts the lines in which the autofocusingregion is included, and sets the light emission duration and theemission commencement time of the external main light source 301 so thatthe light of the external main light source 301 will hit these lines forthe same length of time. The emission commencement time is, for example,the charge accumulation commencement time for the line at which theaccumulation of charge is the latest of all the extracted lines. Theemission duration is, for example, the period from the chargeaccumulation commencement time until the charge accumulation end time(charge reading commencement time) for the line at which theaccumulation of charge ends earliest of all the extracted lines. Thecamera controller 140 sends the XSW signal, which expresses the emissioncommencement time with a pulse signal, to the flash controller 303 viathe XSW signal terminal 163 and the XSW signal terminal 363. Informationrelated to the emission duration is sent to the flash controller 303 viathe data signal terminal 162 and the data signal terminal 362 prior tothe start of video autofocusing.

The flash controller 303 sets the upper limit value Ns of a timer on thebasis of information related to the emission duration prior to the startof video autofocusing. When an XSW signal is then received, the externalmain light source 301 begins emitting light, and the counting of thetimer is started. Once the timer reaches the upper limit value Ns, theemission of light from the external main light source 301 is ended, andthe timer is reset. In this way the external main light source 301 emitslight intermittently.

After image data is acquired for the autofocusing region, the cameracontroller 140 calculates an evaluation value on the basis of this data.An adequate evaluation value can be acquired by having the external mainlight source 301 emit light for the exposure duration of theautofocusing region (the charge accumulation duration).

Once video autofocusing is finished, the camera controller 140 sendsinformation indicating the end of intermittent emission to the flashcontroller 303 via the data signal terminal 162 and the data signalterminal 362. The flash controller 303 ends the intermittent emissioncontrol mode.

If it is decided in step SO4 that an external flash is mounted, then thecamera controller 140 causes the external main light source 301 to emitlight via the flash controller 303 when still picture photography isperformed after video autofocusing. The camera controller 140 may alsocontrol the external main light source 301 so as to prohibit lightemission.

3: Aspects

As described above, with this camera body 100, if it is decided to useauxiliary light, and it is decided that the external auxiliary lightsource of the external flash is not compatible with video autofocusing,the CMOS image sensor 110 and the external flash are controlled so thatimage data is acquired while the external main light source of theexternal flash emits light intermittently. Accordingly, even if anexternal flash that is not compatible with video autofocusing (such asthe external flash 400) is mounted, video autofocusing can still beperformed by using the external main light source, and there will be nodecrease in video autofocusing precision with an external flash that isnot compatible with video autofocusing.

Also, if an external flash that is compatible with video autofocusing(such as the external flash 300) is mounted to the camera body 100,video autofocusing can be performed by using the external auxiliarylight source.

In other words, with this camera body 100, it is possible to ensureinterchangeability with various external flashes.

Also, if it is decided to use auxiliary light, and it is decided thatthe external auxiliary light source of the external flash is notcompatible with video autofocusing, the external flash is controlled sothat the external main light source emits light intermittently insynchronization with the charge accumulation duration of the CMOS imagesensor 110. Accordingly, the precision of the evaluation value can beincreased, and video autofocusing precision can be improved.

Furthermore, the camera controller 140 acquires video autofocusinginformation related to whether or not the external auxiliary lightsource is compatible with video autofocusing from the external flashmounted to the hot shoe 161, and decides whether or not the externalauxiliary light source is compatible with video autofocusing on thebasis of video autofocusing information.

More precisely, the camera controller 140 decides that the externalauxiliary light source is compatible with video autofocusing if thevideo autofocusing information is video autofocusing compatible, anddecides that the external auxiliary light source is not compatible withvideo autofocusing if the video autofocusing information is videoautofocusing incompatible. Also, taking into account the fact that anexternal flash that is not compatible with video autofocusing is verylikely not to have video autofocusing information, the camera controller140 decides that the external auxiliary light source is not compatiblewith video autofocusing if video autofocusing information cannot beacquired from the external flash.

With the above configuration, whether or not an external flash iscompatible with video autofocusing can be accurately decided. Also, evenif an external flash for which video autofocusing compatibility was notoriginally taken into account is mounted, the precision of videoautofocusing can be ensured for the camera body 100 in a photographysituation that requires auxiliary light.

Second Embodiment

The following description will focus on differences from the camera body100 in the first embodiment, and portions that are shared with the firstembodiment will not be described again. Also, components that havesubstantially the same function as in the first embodiment will benumbered the same. The camera body 100 according to the secondembodiment differs from the camera body 100 of the first embodiment inits operation when an external flash that is not compatible with videoautofocusing is mounted. The rest of the configuration is the same asthat in the first embodiment.

FIG. 12 is a flowchart related to the use of auxiliary light duringvideo autofocusing in a second embodiment. The operation from step SO1to step S07 is the same as in the first embodiment.

As shown in FIG. 12, if it is decided that the external flash is notcompatible with video autofocusing (No in step S06), such as when theexternal flash 400 is mounted to the hot shoe 161, the camera controller140 causes the external auxiliary light source 402 to emit light via theflash controller 303, and video autofocusing is performed in a state inwhich light from the external auxiliary light source 402 is shined onthe subject (step S09). The light from the external auxiliary lightsource 402 is very likely to be near infrared light, so most of thelight from the subject is cut out by the optical filter 114. And sincevery little light is transmitted by the optical filter 114, the imagereproduced from image data acquired by the CMOS image sensor 110 is notbright.

In view of this, the CMOS image sensor 110 emphasizes the signal frompixels where a red color filter is disposed during video autofocusingmore than during still picture photography. More specifically, the ratioof the amplification factor of signals outputted from pixels where a redcolor filter is disposed (hereinafter also referred to as the redamplification factor) to the amplification factor of signals outputtedfrom pixels where a blue color filter is disposed (hereinafter alsoreferred to as the blue amplification factor) during video autofocusingis increased over the ratio of the red amplification factor to the blueamplification factor during still picture photography. Also, the ratioof the amplification factor of the red amplification factor to theamplification factor of signals outputted from pixels where a greencolor filter is disposed (hereinafter also referred to as the greenamplification factor) during video autofocusing is increased over theratio of the red amplification factor to the green amplification factorduring still picture photography. Increasing the red amplificationfactor while suppressing the generation of noise in image data bysuppressing the blue and green amplification factors increases theprecision of the evaluation value based on image data for the subjectproduced using the light from the external auxiliary light source 402.Another method is to produce image data and calculate an evaluationvalue by using only signals from pixels where a red color filter isdisposed, and not using signals from pixels where color filters of theother colors (blue and green) are disposed.

At the position of the focus lens 230 where the evaluation value isgreatest, the light from the external auxiliary light source 402, whichhas a high probability of being near infrared light, is focused on theCMOS image sensor 110. Accordingly, correction is necessary so that thefocal point of the light during photography will be located on theimaging face of the CMOS image sensor 110. This will be described indetail through reference to FIG. 10B. FIG. 10B is a concept diagram offocal position correction in the case of external auxiliary light thatis video autofocusing incompatible.

The lens unit 200 also stores a second correction amount X2 in additionto the first correction amount X1. The amount of deviation in the focalposition of the reference light and near infrared light corresponding tothe position of the focus lens 230 and the position of the zoom lens,respectively, is calculated or measured as a design value. The lens unit200 stores an amount X2 (hereinafter also referred to as the secondcorrection amount) that the focus lens 230 is moved in order to correctthe deviation in the focal positions of the near infrared light and thereference light, according to the position of the zoom lens 210 and theposition of the focus lens 230, respectively. Put another way, thesecond correction amount X2 is information indicating how much the focuslens 230 has to be moved from a state in which the near infrared lightis focused on the CMOS image sensor 110 for the reference light to befocused on the CMOS image sensor 110. The camera controller 140 acquiresfrom the lens controller 240 of the lens unit 200 data related to therelation between the second correction amount X2 and the position of thezoom lens and the position of the focus lens 230 when the power isturned on. When the near infrared light from the external auxiliarylight source 402 of the external flash 400, which is video autofocusingincompatible, is shined on the subject and video autofocusing isperformed (step S09), the focus lens 230 is moved from its position atwhich the evaluation value was greatest, by the second correction amountX2 corresponding to the position of the focus lens 230 and the positionof the zoom lens. Consequently, the reference light is focused on theCMOS image sensor 110.

With this embodiment, it is possible to perform video autofocusing bymounting the external flash 400, which is not compatible with videoautofocusing, to the camera body 100. Therefore, it is possible toprovide an autofocusing-compatible interchangeable lens type of digitalcamera that has interchangeability with external flashes.

Third Embodiment

The following description will focus on differences from the camera body100 in the first embodiment, and portions that are shared with the firstembodiment will not be described again. Also, components that havesubstantially the same function as in the first embodiment will benumbered the same. The camera body 100 according to the third embodimentdiffers from the camera body 100 of the first embodiment in itsoperation when an external flash that is not compatible with videoautofocusing is mounted. The rest of the configuration is the same asthat in the first embodiment.

FIG. 13 is a flowchart related to the use of auxiliary light duringvideo autofocusing in a third embodiment. The operation from step SO1 tostep S07 is the same as in the first embodiment.

As shown in FIG. 13, if it is decided to use auxiliary light, and theexternal flash decision part 145 decides that the external flash is notcompatible with video autofocusing (No in step S06), the light emissioncontroller 147 causes the internal main light source 191 to emit lightduring video autofocusing, and the camera controller 140 performs videoautofocusing in a state in which light is shined intermittently on thesubject (step S10). More specifically, the intermittent emission of theinternal main light source 191 is performed instead of the intermittentemission of the external main light source 301 in step S08 in the firstembodiment, and the rest of the operation is the same as in step S08 inthe first embodiment. The intermittent emission of the internal mainlight source 191 is synchronized with the charge accumulation period ofthe CMOS image sensor 110.

Here again, it is possible to perform video autofocusing by mounting anexternal flash that is not compatible with video autofocusing to thecamera body 100. Therefore, it is possible to provide a camera body 100with which interchangeability with various external flashes can beensured.

Fourth Embodiment

The following description will focus on differences from the camera body100 in the first embodiment, and portions that are shared with the firstembodiment will not be described again. Also, components that havesubstantially the same function as in the first embodiment will benumbered the same. The camera body 100 according to the fourthembodiment differs from the camera body 100 of the first embodiment inits operation when an external flash that is not compatible with videoautofocusing is mounted. The rest of the configuration is the same asthat in the first embodiment.

FIG. 14 is a flowchart related to the use of auxiliary light duringvideo autofocusing in a fourth embodiment. The operation from step SO1to step S07 is the same as in the first embodiment.

As shown in FIG. 14, if it is decided to use auxiliary light, and it isdecided that the external flash is not compatible with videoautofocusing (that is, that the external flash mounted to the hot shoe161 has an external auxiliary light source that emits near infraredlight) (No in step S06), the camera controller 140 controls the internalauxiliary light source so that the internal auxiliary light source 192emits light intermittently during video autofocusing, and videoautofocusing is performed in a state in which light is shined on thesubject (step S11). More specifically, the same operation as in step S05of the first embodiment is performed.

Here again, it is possible to perform video autofocusing by mounting anexternal flash that is not compatible with video autofocusing to thecamera body 100. Therefore, it is possible to provide a camera body 100with which interchangeability with various external flashes can beensured.

In this embodiment, the internal auxiliary light source 192 ispreferably a light source that emits a relatively large amount of light.

Fifth Embodiment

The following description will focus on differences from the camera body100 in the first embodiment, and portions that are shared with the firstembodiment will not be described again. Also, components that havesubstantially the same function as in the first embodiment will benumbered the same. The camera body 100 according to the fifth embodimentdiffers from the camera body 100 of the first embodiment in itsoperation when an external flash that is not compatible with videoautofocusing is mounted. The rest of the configuration is the same asthat in the first embodiment.

FIG. 15 is a flowchart related to the use of auxiliary light duringvideo autofocusing in a fourth embodiment. The operation from step SO1to step S07 is the same as in the first embodiment.

As shown in FIG. 15, if it is decided that the external flash is notcompatible with video autofocusing (No in step S06), such as when theexternal flash 400 is mounted, the camera controller 140 causes theinternal main light source 191 (an example of a light source) to emitlight continuously (rather than intermittently), and video autofocusingis performed in a state in which light is shined on the subject (stepS12).

In this embodiment, the internal main light source 191 can emit not onlya flash, but also continuously. The internal main light source 191 alsofunctions as a video light that continuously shines light on the subjectduring video photography, for example.

With this embodiment, it is possible to perform video autofocusing bymounting an external flash 400 that is not compatible with videoautofocusing to the camera body 100. Therefore, it is possible toprovide a camera body 100 with which interchangeability with variousexternal flashes can be ensured.

In this embodiment, the internal auxiliary light source 192 preferablyemits a large amount of light.

Other Embodiments

The technology disclosed herein is not limited to or by the aboveembodiments, and the following embodiments are also possible asembodiments of this technology.

(A)

In the above embodiments, both the internal main light source 191 andthe internal auxiliary light source 192 were provided, but one or bothof these may be eliminated.

(B)

In step S06 above, whether or not the external flash is compatible withvideo autofocusing is decided on the basis of video autofocusinginformation (or, whether or not the external flash has an externalauxiliary light source that emits near infrared light is decided on thebasis of light source identification information), but rather than usingspecial information such as video autofocusing information, whether ornot the external flash is compatible with video autofocusing may bedecided using standard information. More specifically, it is possible todecide whether or not an external flash is compatible with videoautofocusing on the basis of product identification information such asa stock number or model number that allows the external flash to beidentified.

For example, product identification information such as a stock numberor model number is stored in the flash controller of an external flash,and the camera controller 140 acquires the product identificationinformation from the external flash mounted to the hot shoe 161 anddecides whether or not the external auxiliary light source is compatiblewith video autofocusing on the basis of this product identificationinformation.

In this case, the camera controller 140 stores a product list includingproduct identification information about external flashes that have anexternal auxiliary light source that is compatible with videoautofocusing, and if the product identification information acquiredfrom the external flash mounted to the hot shoe 161 is included in theproduct list, it is decided that the external auxiliary light source ofthe external flash mounted to the hot shoe 161 is compatible with videoautofocusing, but if the product identification information acquiredfrom the external flash mounted to the hot shoe 161 is not included inthe product list, it is decided that the external auxiliary light sourceof the external flash mounted to the hot shoe 161 is not compatible withvideo autofocusing.

Conversely, it is also possible to store a product list includingproduct identification information about external flashes that have anexternal auxiliary light source that is not compatible with videoautofocusing. More specifically, the camera controller 140 decides thatthe external auxiliary light source of the external flash mounted to thehot shoe 161 is compatible with video autofocusing if the productidentification information acquired from the external flash mounted tothe hot shoe 161 is not included in the product list, and decides thatthe external auxiliary light source of the external flash mounted to thehot shoe 161 is not compatible with video autofocusing if the productidentification information acquired from the external flash mounted tothe hot shoe 161 is included in the product list.

By using product identification information as discussed above, whetheror not an external flash is compatible with video autofocusing can beaccurately decided, just as with the embodiments given above. Hereagain, an external auxiliary light source is considered to be compatiblewith video autofocusing if its light is visible light that includes red.

One or more types of product identification information may be includedin the product list.

(C)

In the embodiments, both the camera monitor 120 and the EVF 180 wereprovided, but the camera monitor 120 and/or the EVF 180 may beeliminated.

(D)

In the embodiments, an example was given of a configuration having theOIS lens 220, but this is not essential to the present invention.Specifically, the present invention can also be applied to a digitalcamera to which is mounted an interchangeable lens that does not have ashake correction function.

(E)

The electrical contacts 153 may be supported by the body mount ring 151.For instance, the electrical contacts 153 may be provided between theinner periphery and outer periphery of the body mount ring 151.

(F)

In the above embodiments, the camera body 100, unlike a single lensreflex camera, does not have a mirror box device, nor does it have aphase difference detection unit that receives subject light guided by amirror box device and performs phase difference autofocusing.

However, the camera body 100 may have a phase difference detection unitthat that receives subject light guided by a mirror box device andperforms phase difference autofocusing. In this case, the camera body100 retracts the mirror of the mirror box device from the optical path,and performs video autofocusing on the basis of image data acquired bythe CMOS image sensor 110. More specifically, contrast autofocusing isperformed by changing the position of the focus lens 230 andsuccessively calculating evaluation values for contrast from the imagedata obtained from the CMOS image sensor 110. Even when videoautofocusing is thus performed with a single lens reflex camera, theoperation can be carried out as in the embodiments and videoautofocusing can be performed by mounting a conventional flash device.

(G)

In steps S08, S10, and S11, the external auxiliary light source 302 mayor may not emit light.

(H)

In step S12 in the fifth embodiment, a light source provided to thecamera body separately from the internal main light source 191 (such asa video light (an example of an internal light source)) may emit light.

Aspects of Embodiments

The technology described above can be expressed as follows. Thetechnology included in the above embodiments is not, however, limited towhat is stated below. To obtain the effects discussed in the variousaspects, configurations other than those of the given aspects may bemodified or eliminated.

Aspect 1

The camera body according to aspect 1 comprises:

a body mount that supports a removable lens unit;

an imaging element that captures an optical image of a subject andproduces image data;

a hot shoe that supports a removable flash device; and

a camera controller that calculates an evaluation value on the basis ofimage data from the imaging element, and performs video autofocusing,

wherein the camera controller controls so that when it is decided to useauxiliary light, and a flash device having an external auxiliary lightsource that is not compatible with video autofocusing is mounted, theexternal flash light source of the flash device is made to emit lightintermittently, and the imaging element is made to acquire image data,and an evaluation value is calculated on the basis of this image data.

Consequently, it is possible to provide an interchangeable lens type ofdigital camera that is capable of video autofocusing and hasinterchangeability with conventional flash devices.

Aspect 2

The camera body according to aspect 2 is the camera body according toaspect 1,

wherein, when it is decided to use auxiliary light, and a flash devicehaving an external auxiliary light source that is not compatible withvideo autofocusing is mounted, the camera controller causes the externalflash light source of the flash device to emit light intermittently insynchronization with the charge accumulation duration of the imagingelement used to acquire the image data.

Consequently, video autofocusing of high precision is possible by usinga conventional flash device even when the subject is dark.

Aspect 3

The camera body according to aspect 3 comprises:

a body mount that supports a removable lens unit;

an imaging element that captures an optical image of a subject andproduces image data;

a hot shoe that supports a removable flash device; and

a camera controller that calculates an evaluation value on the basis ofimage data from the imaging element, and performs video autofocusing,

wherein the camera controller controls the imaging element so that whenit is decided to use auxiliary light, and a flash device having anexternal auxiliary light source that is not compatible with videoautofocusing is mounted, the external flash light source of the flashdevice is made to emit light, and image data is acquired by emphasizingsignals from pixels where a red color filter is disposed more thanduring still picture photography.

Consequently, it is possible to provide an interchangeable lens type ofdigital camera that is capable of video autofocusing and hasinterchangeability with conventional flash devices.

Aspect 4

The camera body according to aspect 4 is the camera body according toaspect 3,

wherein the imaging element is controlled so that the image data isacquired by emphasizing signals from pixels where a red color filter isdisposed more than during still picture photography, by controlling theimaging element so that the image data is acquired by increasing theratio of the amplification factor of signals from pixels where a redcolor filter is disposed to the amplification factor of signals frompixels where a blue color filter is disposed during video autofocusingover the ratio of the amplification factor of signals from pixels wherea red color filter is disposed to the amplification factor of signalsfrom pixels where a blue color filter is disposed during still picturephotography, and/or the increasing ratio of the amplification factor ofsignals from pixels where a red color filter is disposed to theamplification factor of signals from pixels where a green color filteris disposed during video autofocusing over the ratio of theamplification factor of signals from pixels where a red color filter isdisposed to the amplification factor of signals from pixels where agreen color filter is disposed during still picture photography.

Consequently, an increase in image data noise can be suppressed whileraising the precision of the evaluation value based on image data of thesubject illuminated with light from the external auxiliary light source.

Aspect 5

The camera body according to aspect 5 is the camera body according toaspect 3,

wherein the camera controller controls the imaging element so that imagedata is acquired by emphasizing signals from pixels where a red colorfilter is disposed more than during still picture photography, bycontrolling the imaging element so that image data is acquired solely onthe basis of signals from pixels where a red color filter is disposed.

Consequently, an increase in image data noise can be suppressed whileraising the precision of the evaluation value based on image data of thesubject illuminated with light from the external auxiliary light source.

Aspect 6

The camera body according to aspect 6 is the camera body according toany of aspects 3 to 5,

wherein the camera controller corrects deviation in the focal positionbetween reference light and the light from an external auxiliary lightsource that is compatible with video autofocusing in the performance ofvideo autofocusing in which an external auxiliary light source that iscompatible with video autofocusing is made to emit light, and correctsdeviation in the focal position between reference light and the light ofan external auxiliary light source that is not compatible with videoautofocusing in the performance of video autofocusing in which anexternal auxiliary light source that is not compatible with videoautofocusing is made to emit light.

Consequently, focal precision can be enhanced.

Aspect 7

The camera body according to aspect 7 is the camera body according toany of aspects 3 to 5,

wherein the camera controller uses a first correction amount that is theamount the focus lens is moved in order to correct deviation in thefocal position between reference light and the light of an externalauxiliary light source that is compatible with video autofocusing in theperformance of video autofocusing in which an external auxiliary lightsource that is compatible with video autofocusing is made to emit light,and uses a second correction amount that is the amount the focus lens ismoved in order to correct deviation in the focal position betweenreference light and the light of an external auxiliary light source thatis not compatible with video autofocusing in the performance of videoautofocusing in which an external auxiliary light source that is notcompatible with video autofocusing is made to emit light.

Consequently, focal precision can be enhanced.

Aspect 8

The camera body according to aspect 8 comprises:

a body mount that supports a removable lens unit;

an imaging element that captures an optical image of a subject andproduces image data;

a hot shoe that supports a removable flash device;

a light source capable of emitting light; and

a camera controller that calculates an evaluation value on the basis ofimage data from the imaging element, and performs video autofocusing,

wherein the camera controller controls so that when it is decided to useauxiliary light, and a flash device having an external auxiliary lightsource that is not compatible with video autofocusing is mounted, thelight source is made to emit light, and the imaging element is made toacquire image data, and an evaluation value is calculated on the basisof this image data.

Consequently, it is possible to provide an interchangeable lens type ofdigital camera that is capable of video autofocusing and hasinterchangeability with conventional flash devices.

Aspect 9

The camera body according to aspect 9 is the camera body according toaspect 8,

wherein the light source is an internal flash capable of emitting flashlight, and

when it is decided to use auxiliary light, and a flash device having anexternal auxiliary light source that is not compatible with videoautofocusing is mounted, the camera controller causes the internal flashto emit light intermittently and causes the imaging element to acquireimaging device, and an evaluation value is calculated on the basis ofthis image data.

Aspect 10

The camera body according to aspect 10 is the camera body according toaspect 9,

wherein, when it is decided to use auxiliary light, and a flash devicehaving an external auxiliary light source that is not compatible withvideo autofocusing is mounted, the camera controller causes the internalflash to emit light intermittently in synchronization with the chargeaccumulation duration of the imaging element used to acquire the imagedata.

Aspect 11

The camera body according to aspect 11 is the camera body according toaspect 8,

wherein the light source is an internal auxiliary light source capableof shining light on a subject, and

when it is decided to use auxiliary light, and a flash device having anexternal auxiliary light source that is not compatible with videoautofocusing is mounted, the camera controller causes the internalauxiliary light source to emit light and causes the imaging element toacquire imaging device, and an evaluation value is calculated on thebasis of this image data.

Aspect 12

The camera body according to aspect 12 is the camera body according toany of aspects 1 to 11,

wherein the camera controller acquires from the flash device informationabout the possibility of video autofocusing related to whether or not anexternal auxiliary light source is compatible with video autofocusing,and decides whether or not the external auxiliary light source of theflash device is compatible with video autofocusing on the basis of thisvideo autofocusing possibility information.

Aspect 13

The camera body according to aspect 13 is the camera body according toaspect 12,

wherein the camera controller decides that the external auxiliary lightsource of the mounted flash device is compatible with video autofocusingif the video autofocusing possibility information indicates that videoautofocusing is possible, and decides that the external auxiliary lightsource of the mounted flash device is incompatible with videoautofocusing if the video autofocusing possibility information indicatesthat video autofocusing is impossible.

Aspect 14

The camera body according to aspect 14 is the camera body according toany of aspects 1 to 11,

wherein the camera controller acquires from the flash device stocknumber information related to the stock number of the mounted flashdevice, and decides whether or not the external auxiliary light sourceof the flash device is compatible with video autofocusing on the basisof this stock number information.

Aspect 15

The camera body according to aspect 15 is the camera body according toaspect 14,

wherein the camera controller stores a list of stock number informationabout flash devices that have an external auxiliary light source that iscompatible with video autofocusing, and decides that the externalauxiliary light source of the mounted flash device is compatible withvideo autofocusing if the stock number information acquired from themounted flash device matches the stock number information of the list,and decides that the external auxiliary light source of the mountedflash device is incompatible with video autofocusing if the stock numberinformation acquired from the mounted flash device does not match thestock number information of the list.

Aspect 16

The camera body according to aspect 16 is the camera body according toaspect 14,

wherein the stores a list of stock number information about flashdevices that have an external auxiliary light source that is notcompatible with video autofocusing, and decides that the externalauxiliary light source of the mounted flash device is compatible withvideo autofocusing if the stock number information acquired from themounted flash device does not match the stock number information of thelist, and decides that the external auxiliary light source of themounted flash device is incompatible with video autofocusing if thestock number information acquired from the mounted flash device matchesthe stock number information of the list

Aspect 17

The camera body according to aspect 17 comprises:

a body mount that supports a removable lens unit;

an imaging element that captures an optical image of a subject andproduces image data;

a hot shoe that supports a removable flash device; and

a camera controller that calculates an evaluation value on the basis ofimage data from the imaging element, and performs video autofocusing,

wherein the camera controller controls so that when it is decided to useauxiliary light, and a flash device having an external auxiliary lightsource that emits near infrared light is mounted, the external flashlight source of the flash device is made to emit light intermittently,and the imaging element is made to acquire image data, and an evaluationvalue is calculated on the basis of this image data.

Aspect 18

The camera body according to aspect 18 is the camera body according toaspect 17,

wherein, when it is decided to use auxiliary light, and a flash devicehaving an external auxiliary light source that emits near infrared lightis mounted, the camera controller causes the external flash light sourceof the flash device to emit light intermittently in synchronization withthe charge accumulation duration of the imaging element used to acquirethe image data.

Aspect 19

The camera body according to claim 19 comprises:

a body mount that supports a removable lens unit;

an imaging element that captures an optical image of a subject andproduces image data;

a hot shoe that supports a removable flash device; and

a camera controller that calculates an evaluation value on the basis ofimage data from the imaging element, and performs video autofocusing,

wherein the camera controller controls the imaging element so that whenit is decided to use auxiliary light, and a flash device having anexternal auxiliary light source that emits near infrared light ismounted, the external auxiliary light source of the flash device is madeto emit light, and image data is acquired by emphasizing signals frompixels where a red color filter is disposed more than during stillpicture photography.

Aspect 20

The camera body according to aspect 20 is the camera body according toaspect 19

wherein the imaging element is controlled so that the image data isacquired by emphasizing signals from pixels where a red color filter isdisposed more than during still picture photography, by controlling theimaging element so that the image data is acquired by increasing theratio of the amplification factor of signals from pixels where a redcolor filter is disposed to the amplification factor of signals frompixels where a blue color filter is disposed during video autofocusingover the ratio of the amplification factor of signals from pixels wherea red color filter is disposed to the amplification factor of signalsfrom pixels where a blue color filter is disposed during still picturephotography, and/or the increasing ratio of the amplification factor ofsignals from pixels where a red color filter is disposed to theamplification factor of signals from pixels where a green color filteris disposed during video autofocusing over the ratio of theamplification factor of signals from pixels where a red color filter isdisposed to the amplification factor of signals from pixels where agreen color filter is disposed during still picture photography.

Aspect 21

The camera body according to aspect 21 is the camera body according toaspect 19,

wherein the camera controller controls the imaging element so that imagedata is acquired by emphasizing signals from pixels where a red colorfilter is disposed more than during still picture photography, bycontrolling the imaging element so that image data is acquired solely onthe basis of signals from pixels where a red color filter is disposed.

Aspect 22

The camera body according to aspect 22 is the camera body according toany of aspects 19 to 21,

wherein the camera controller corrects deviation in the focal positionbetween reference light and red light in the performance of videoautofocusing in which an external auxiliary light source that emits redlight is made to emit light, and corrects deviation in the focalposition between reference light and near infrared light in theperformance of video autofocusing in which an external auxiliary lightsource that emits near infrared light is made to emit light.

Aspect 23

The camera body according to aspect 23 is the camera body according toany of aspects 19 to 21,

wherein the camera controller uses a first correction amount that is theamount the focus lens is moved in order to correct deviation in thefocal position between reference light and red light in the performanceof video autofocusing in which an external auxiliary light source thatemits red light is made to emit light, and uses a second correctionamount that is the amount the focus lens is moved in order to correctdeviation in the focal position between reference light and nearinfrared light in the performance of video autofocusing in which anexternal auxiliary light source that emits near infrared light is madeto emit light.

Aspect 24

The camera body according to aspect 24 comprises:

a body mount that supports a removable lens unit;

an imaging element that captures an optical image of a subject andproduces image data;

a hot shoe that supports a removable flash device;

a light source capable of emitting light; and

a camera controller that calculates an evaluation value on the basis ofimage data from the imaging element, and performs video autofocusing,

wherein the camera controller controls so that when it is decided to useauxiliary light, and a flash device having an external auxiliary lightsource that emits near infrared light is mounted, the light source ismade to emit light, and the imaging element is made to acquire imagedata, and an evaluation value is calculated on the basis of this imagedata.

Aspect 25

The camera body according to aspect 25 is the camera body according toaspect 24,

wherein the light source is an internal flash capable of emitting flashlight, and

when it is decided to use auxiliary light, and a flash device having anexternal auxiliary light source that emits near infrared light ismounted, the camera controller causes the internal flash to emit lightintermittently and causes the imaging element to acquire imaging device,and an evaluation value is calculated on the basis of this image data.

Aspect 26

The camera body according to aspect 26 is the camera body according toaspect 25,

wherein, when it is decided to use auxiliary light, and a flash devicehaving an external auxiliary light source that emits near infrared lightis mounted, the camera controller causes the internal flash to emitlight intermittently in synchronization with the charge accumulationduration of the imaging element used to acquire the image data.

Aspect 27

The camera body according to aspect 27 is the camera body according toaspect 24,

wherein the light source is an internal auxiliary light source capableof shining light on a subject, and

when it is decided to use auxiliary light, and a flash device having anexternal auxiliary light source that emits near infrared light ismounted, the camera controller causes the internal auxiliary lightsource to emit light and causes the imaging element to acquire imagingdevice, and an evaluation value is calculated on the basis of this imagedata.

1. A camera body to which a lens unit for forming an optical image of asubject and a flash device for shining light on the subject can bemounted, comprising: an imaging element configured to convert an opticalimage of the subject into an electrical signal, and configured toproduce image data for the subject; a hot shoe to which the flash devicecan be mounted; an internal light source arranged to shine light on thesubject; and a camera controller configured to calculate an evaluationvalue on the basis of the image data produced by the imaging element,and configured to perform video autofocusing on the basis of theevaluation value, the camera controller configured to control theimaging element and the internal light source so that when the cameracontroller decides auxiliary light is needed, and the camera controllerdecides that the flash device mounted to the hot shoe has an externalauxiliary light source arranged to emit near infrared light, the imagedata is acquired while the internal light source emits light during thevideo autofocusing, wherein the camera controller is configured toacquire, from the flash device mounted to the hot shoe, light sourceidentification information related to whether or not the flash devicehas the external auxiliary light source arranged to emit near infraredlight and is configured to decide whether or not the flash device hasthe external auxiliary light source on the basis of the light sourceidentification information.
 2. The camera body according to claim 1,wherein the internal light source is an internal main light sourcearranged to shine light on the subject, and the camera controller isconfigured to control the internal main light source so that when thecamera controller decides that the auxiliary light is needed, and thecamera controller decides that the flash device mounted to the hot shoehas the external auxiliary light source arranged to emit near infraredlight, the internal main light source emits light intermittently duringthe video autofocusing.
 3. The camera body according to claim 2,wherein, the camera controller is configured to control the internalmain light source so that when the camera controller decides that theauxiliary light is needed, and the camera controller decides that theflash device mounted to the hot shoe has the external auxiliary lightsource arranged to emit near infrared light, the internal main lightsource emits light intermittently and in synchronization with the chargeaccumulation period of the imaging element.
 4. The camera body accordingto claim 2, wherein the camera controller is configured to acquire, fromthe flash device mounted to the hot shoe, light source identificationinformation related to whether or not the flash device has the externalauxiliary light source arranged to emit near infrared light, and isconfigured to decide whether or not the flash device has the externalauxiliary light source on the basis of the light source identificationinformation.
 5. The camera body according to claim 1, wherein theinternal light source is an internal auxiliary light source for shininglight on the subject, and the camera controller is configured to controlthe internal auxiliary light source so that when the camera controllerdecides that the auxiliary light is needed, and the camera controllerdecides that the flash device mounted to the hot shoe has the externalauxiliary light source arranged to emit near infrared light, theinternal auxiliary light source emits light intermittently during thevideo autofocusing.
 6. The camera body according to claim 1, wherein thecamera controller is configured to decide that the flash device has theexternal auxiliary light source arranged to emit near infrared light ifthe light source identification information cannot be acquired from theflash device.
 7. The camera body according to claim 1, wherein thecamera controller has an auxiliary light determination part configure todecide whether or not to use the auxiliary light; a flash devicedecision part configured to decide whether or not the flash devicemounted to the hot shoe has the external auxiliary light source arrangedto emit near infrared light; and a light emission controller configuredto control the flash device on the basis of a first decision result ofthe auxiliary light determination part and a second decision result ofthe auxiliary light determination part, so that an external main lightsource emits light intermittently during the video autofocusing.
 8. Acamera body to which a lens unit for forming an optical image of asubject and a flash device for shining light on the subject can bemounted, comprising: an imaging element configured to convert an opticalimage of the subject into an electrical signal, and configured toproduce image data for the subject a hot shoe to which the flash devicecan be mounted; an internal light source arranged to shine light on thesubject and a camera controller configured to calculate an evaluationvalue on the basis of the image data produced by the imaging element,and configured to perform video autofocusing on the basis of theevaluation value, the camera controller configured to control theimaging element and the internal light source so that when the cameracontroller decides the auxiliary light is needed, and the cameracontroller decides that the flash device mounted to the hot shoe has anexternal auxiliary light source arranged to emit near infrared light,the image data is acquired while the internal light source emits lightduring the video autofocusing, wherein the camera controller isconfigured to acquire, from the flash device mounted to the hot shoe,product identification information for identifying the flash device, andis configured to decide whether or not the flash device has the externalauxiliary light source on the basis of the product identificationinformation.
 9. The camera body according to claim 8, wherein the cameracontroller stores a product list including product identificationinformation about flash devices having the external auxiliary lightsource arranged to emit near infrared light, if the productidentification information acquired from the flash device mounted to thehot shoe is included in the product list, the camera controller decidesthat the external auxiliary light source of the flash device mounted tothe hot shoe is compatible with the video autofocusing, and if theproduct identification information acquired from the flash devicemounted to the hot shoe is not included in the product list, the cameracontroller decides that the mounted flash device has the externalauxiliary light source arranged to emit near infrared light.
 10. Thecamera body according to claim 8, wherein the camera controller stores aproduct list including product identification information about flashdevices not having the external auxiliary light source arranged to emitnear infrared light, if the product identification information acquiredfrom the flash device mounted to the hot shoe is not included in theproduct list, the camera controller decides that the flash devicemounted to the hot shoe has the external auxiliary light source arrangedto emit near infrared light, and if the product identificationinformation acquired from the flash device mounted to the hot shoe isincluded in the product list, the camera controller decides that theflash device mounted to the hot shoe does not have the externalauxiliary light source arranged to emit near infrared light.